Method of detinning tin schap and the like



Patented Oct. 23, 1923.

UNITED STATES EMANUEL KARDOS, 0F NEWARK, NEW JERSEY.

METHOD OF DETINNING TIN SCRAP AND THE LIKE.

1T0 Drawing.

To all whom it may concern:

Be it known that I, EMANUEL Kannos, a citizen of Hungary, and residentof Newark, in the county of Essex and State of New Jersey, have inventeda certain new and useful Method of Detinning Tin Scrap and the like, ofwhich the following is a specification.

The invention relates to a method of detinning tin scrap and the like inorder to recover the tin and the high grade iron used in the manufactureof tin plate. Heretofore, various electrolytic and chemical processeshave been proposed for this purpose, but all former methods have beeneither expensive, rendering the cost of recovery inordinately high, orhave been inell'ective to produce a complete recovery of the tin. Theobject of the present invention is to provide a method \vhlch is at onceeconomical and efficient of application, and which also insures thecomplete removal and recovery of the tin and the iron without materialimpairment. of either of these elements.

To these ends the invention comprises the immersion of the tin scrap inan alkaline electrolyte, such, for example, as an aqueous solution ofcaustic soda or potash, in which the tin scrap serves as the positiveelectrode. the negative electrode being coir stituted by a suitablematerial, such as car bon. graphite, manganese dioxide or the like, andboth of the ele trodes bcin; arranged in close, proximity to each otherand preferably in direct contact. and in adding to the malerialsimmersed in the, electrolyte. a suitable oxidizing agent. which alsoacts as a depolarizcr such, for example. as air. saltpctcr. or the.like. For exam le. ex ellent results have been obtained by employing anelcctrolytc solution containing from Your per cent to twelve per cent ofcaustic soda. and from thre per cent to ten per cent of saltpctcrv Theprimary (fle t of the oxidizing and depolarizing agent. when intimatelyassoc ated with the electrodes. and preferably in surface contacttherewith. is to materially in crease the potential that corresponds tothe normal couple represented by the tin scrap and th moreelectro-nea'alire material immersed in the electrolyt and therefore toaccelerate he thorough and complete re moral of the tin from the scrap.The main- Application filed April 14, 1920. Serial No. 373,957.

tenance of a relatively high potential between the electrodes may alsobe etfect d by increasing the surface of the negative electrode exposedto the electrolyte, more especially when the negative electrode iscarbon, graphite, manganese dioxide or the like.

In the preferred application of the method aforesaid, the tin scrap,constituting the positive electrode, is placed in baskets of a moreelectro-negative material, or in conve ors of such material, whichaffords a re atively large surface exposure, and is im-- merscd Within atank or vat containing an electrolyte of the character described, towhich an oxidizing agent, such as air, saltpeter, or the like, has beenadded.

The electromegative material may either be mixed with the tin scrap, ormay consti tute an outer or inner lining of the basket. conveyor, or thelike, or may be applied in any other suitable manner in connection withthe basket or conveyor provided the materials are arranged and disposedin close proximity to each other.

lVhat I claim is:

l. The method of detinning tin scrap which comprises subjecting thescrap as anode to the action of an alkaline bath in the presence of amaterial electro-m-gative to the tin associated with an oxidizing agent.

2. The method of detinning tin scrap which omprises immersing the scrapas anode and electrode of materialelectromegatire to the tin in analkaline bath and snpplyinr to the bath an oxidizing agent.

3. The method of dctinning tin scrap whi h comprises placing the scrapas anode in a container consisting of a material elertro-negative to thetin, immersing the container in an alkaline bath and supplying to thebath an oxidizing agent. i

4. The method of dctinning tin s rap which comprises placing the scrapas anode in a container consisting of a material elecfro-negative to thetin. immersing the containcr in an alkaline bath and supplying to thehath an oxidizing agent, and maintain in the electrodes in close, ontactwith one another.

igncd at. Chrome in the county of Middlcsex and State of New Jersey this7th dav of April A. T). 1920.

EMANUEL KA RDOS.

